Role of the adrenal medullae in male and female DOCA-salt hypertensive rats.
Female rats treated with deoxycorticosterone acetate (DOCA) and salt do not get as hypertensive as male DOCA-salt treated rats. The adrenal gland contributes to the development and maintenance of DOCA-salt hypertension in male rats. However, little is known about adrenal medullary function in DOCA-salt hypertensive female rats. This study tested the hypothesis that bilateral removal of the adrenal medullae would result in a greater fall in blood pressure in male DOCA-salt compared to female DOCA-salt rats. Five weeks after initiating DOCA-salt treatment, average 24 hour mean arterial pressure (MAP) in female rats was significantly attenuated compared to male rats (142+/-4 versus 168+/-6 mm Hg, respectively). Female DOCA-salt rats consumed significantly more saline per day than male DOCA-salt rats (22.3+/-1.8 versus 33.4+/-1.8 mL/100 grams body weight, respectively). Following adrenal medullectomy, DOCA-salt males experienced a significant decrease in MAP during the dark period after surgery (182+/-4 to 154+/-4 mm Hg) that was not observed in female DOCA-salt rats (150+/-6 to 135+/-3 mm Hg). In the following light period, MAP remained significantly decreased when compared to the light period before surgery in DOCA-salt male (171+/-4 to 156+/-4 mm Hg), while no effect was observed in DOCA-salt female rats. Adrenal medullectomy significantly increased heart rate (HR) in all groups for 12 days. Male sham and DOCA-salt rats had significantly higher catecholamine content in the adrenal medulla than female sham and DOCA-salt rats, respectively. These data suggest that the adrenal medullae contribute more to the maintenance of blood pressure in DOCA-salt hypertension in male rats than female rats.
Lange
D L
DL
Department of Pharmacology, University of Texas Health Science Center, San Antonio 78284-7756, USA.
Haywood
J R
JR
Hinojosa-Laborde
C
C
D000313:Adrenal Medulla / Q000502:physiology / Q000503:physiopathology*; D000315:Adrenalectomy; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects / Q000502:physiology*; D001835:Body Weight; D003900:Desoxycorticosterone; D004837:Epinephrine / Q000378:metabolism; D005260:Female; D006339:Heart Rate; D006973:Hypertension / Q000139:chemically induced / Q000503:physiopathology*; D008297:Male; D009638:Norepinephrine / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D012727:Sex Characteristics; D012982:Sodium, Dietary; D013997:Time Factors
D012982:Sodium, Dietary; D003900:Desoxycorticosterone; D009638:Norepinephrine; D004837:Epinephrine